Minecraft 1.21.4 keeps crashing with this (Originally an issue from 1 month ago, it got closed by github actions)

[MKstarFromSwitch]

Uncaught exception in thread "main"
java.lang.RuntimeException: Mixin transformation of net.minecraft.client.main.Main failed
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.getPostMixinClassByteArray(KnotClassDelegate.java:427)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.tryLoadClass(KnotClassDelegate.java:323)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.loadClass(KnotClassDelegate.java:218)
at net.fabricmc.loader.impl.launch.knot.KnotClassLoader.loadClass(KnotClassLoader.java:119)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526)
at net.fabricmc.loader.impl.game.minecraft.MinecraftGameProvider.launch(MinecraftGameProvider.java:473)
at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:74)
at net.fabricmc.loader.impl.launch.knot.KnotClient.main(KnotClient.java:23)
Caused by: java.lang.NoClassDefFoundError: feather/lib/sentry/Sentry
at knot//net.digitalingot.feather.pm.nf(FeatherSourceFile:73)
at knot//net.digitalingot.feather.mixin.FeatherMixinPlugin.onLoad(FeatherSourceFile:69)
at org.spongepowered.asm.mixin.transformer.PluginHandle.onLoad(PluginHandle.java:119)
at org.spongepowered.asm.mixin.transformer.MixinConfig.onSelect(MixinConfig.java:790)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.selectConfigs(MixinProcessor.java:498)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.select(MixinProcessor.java:460)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.checkSelect(MixinProcessor.java:438)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.applyMixins(MixinProcessor.java:290)
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClass(MixinTransformer.java:234)
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClassBytes(MixinTransformer.java:202)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.getPostMixinClassByteArray(KnotClassDelegate.java:422)
... 7 more
Caused by: java.lang.ClassNotFoundException: feather.lib.sentry.Sentry
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.loadClass(KnotClassDelegate.java:226)
at net.fabricmc.loader.impl.launch.knot.KnotClassLoader.loadClass(KnotClassLoader.java:119)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526)
... 18 more

[Olafcio1]

I think this is the cause -> https://modrinth.com/mod/featherlib
If it's installed, then remove it. If it's not installed, then install it (the problem is probably that it's not installed)

[MKstarFromSwitch]

I suggest you ask them and let us know what they say

Can't find any way but their discord to get in contact with them, and Discord is banned in my country so I'll have to rely on here or something

[Poopooracoocoo]

Use a VPN or anti-censorship tool like Zapret

[MKstarFromSwitch]

Use a VPN or anti-censorship tool like Zapret

VPNs steal info + I'm the biggest VPN hater. Any alternative ways?

[Poopooracoocoo]

CloudFlare WARP and Proton VPN are well trusted. You don't have to use them permanently. Just to access restricted sites like Discord. I also mentioned Zapret.

Anyway, you may be able to get it to work by editing the Fabric installation and setting the "game directory" to a new folder anywhere.

Or you may want to switch to a third party launcher such as Prism Launcher, the Modrinth App, the CurseForge App. ATLauncher, etc.

[MKstarFromSwitch]

CloudFlare WARP and Proton VPN are well trusted. You don't have to use them permanently. Just to access restricted sites like Discord. I also mentioned Zapret.

Anyway, you may be able to get it to work by editing the Fabric installation and setting the "game directory" to a new folder anywhere.

Or you may want to switch to a third party launcher such as Prism Launcher, the Modrinth App, the CurseForge App. ATLauncher, etc.

My main PC isn't available right now, typing from my side Linux laptop. Will try though.